Field of the Disclosure
The present disclosure relates to cuff pressure controller devices that control the pressure inside the cuff.
Description of the Related Art
In related art, tracheal intubation is well known in medical fields relating to artificial ventilators. In tracheal intubation, a technician such as a medical doctor and the like inserts an intubation tube into trachea of a subject (usually, a human body) from the cavity of mouth or nose to maintain an open airway, and oxygen is sent to lungs via the intubation tube.
When there is a gap between the intubation tube and the inner wall of trachea, secretions such as gastric fluid, saliva, and the like enters trachea, and the subject may be at a high risk of developing ventilator-associated pneumonia (hereinafter, referred to as “VAP”). To block such secretion inflow, a cuff is provided at the outer wall of the intubation tube.
The cuff inflates upon receiving a supply of gas in the cuff. As the cuff inflates, an outer periphery of the cuff comes into contact with the inner wall of trachea and closes trachea. As described above, in related art, airway is secured with the intubation tube while blocking the secretions from entering trachea with the cuff.
In a case where the inner pressure of cuff (hereinafter, referred to as “cuff pressure”) goes out of a predetermined range, a following problem is known to occur.
For example, when the cuff pressure exceeds the predetermined range, the inflated cuff also compresses blood vessels of mucosal tissue of trachea. When the blood vessels are compressed, the blood vessels become ischemic. As a result, necrosis, bleeding, and the like are prone to occur.
On the other hand, when the cuff pressure falls below the predetermined range, the inflation of the cuff becomes insufficient. This may create a gap between the outer periphery of the cuff and the inner wall of trachea, and secretions such as gastric fluid, saliva, and the like may enter trachea.
To address this problem, patent document 1 discloses a cuff pressure controller device that controls the pressure inside the cuff so as to stay within a predetermined range.
FIG. 9 is a block diagram depicting the configuration of various features of a cuff pressure controller device 900 according to the patent document 1. The cuff pressure controller device 900 controls the inner pressure of a cuff 90 (hereinafter, referred to as “cuff pressure”). The cuff pressure controller device 900 includes a control system 910 and a cuff pressure regulator unit 920.
The control system 910 includes a controller unit 911, a cuff pressure detector unit 913, and an alarm unit 916. The controller unit 911 controls each unit in the cuff pressure controller device 900 based on the detection results of the cuff pressure detector unit 913.
The cuff pressure detector unit 913 is connected via a cuff pressure detection tube 918 that is connected to a gas supply tube 925. The cuff pressure detector unit 913 detects the cuff pressure of the cuff 90. The controller unit 911 reads out that cuff pressure from the cuff pressure detector unit 913.
The alarm unit 916 is driven by the controller unit 911, and sounds, for example, an alarm to inform the technician of an anomaly of the cuff 90 and the like.
The cuff pressure regulator unit 920 includes a pressure pump 926, a safety valve 927, a unidirectional valve 921, a release valve 922, a flow volume regulator valve 923, and a reservoir tank 924. The pressure pump 926, the unidirectional valve 921, the safety valve 927, the release valve 922, the flow volume regulator valve 923, and the reservoir tank 924 are connected in this order.
The pressure pump 926 is driven by the controller unit 911, and is an electric pump that applies pressure to the cuff 90 via the gas supply tube 925. In the pressure pump 926, the pressure to be applied to the cuff 90 and its speed are set under the control of the controller unit 911. The unidirectional valve 921 is connected to the downstream side of the pressure pump 926, and prevents backward flow of gas from the cuff 90 side to the pressure pump 926.
The release valve 922 opens and closes in response to the control of the controller unit 911. In the opened state, the release valve 922 releases gas inside the cuff 90 to the atmosphere via the gas supply tube 925, and reduces the pressure of the cuff 90.
The flow volume regulator valve 923 regulates the amount of gas to be supplied to the cuff 90 via the gas supply tube 925. The reservoir tank 924 is connected to the downstream side of the flow volume regulator valve 923, and absorbs cuff pressure variation of the cuff 90.
With the foregoing configuration, the cuff pressure controller device 900 includes the flow volume regulator valve 923 between the pressure pump 926 and the cuff 90, and controls the driving of the flow volume regulator valve 923, the pressure pump 926, and the release valve 922 in such a way that the cuff pressure of the cuff 90 stays inside the predetermined range based on detection results of the cuff pressure detector unit 913. Further, the cuff pressure controller device 900 sounds an alarm to inform anomaly using the alarm unit 916 when the cuff pressure does not stay within the predetermined range.
Patent Document 1: Japanese Unexamined Patent Application Publication No. 2011-194222